Main question is what I am doing wrong in my OpenSwan or L2TP client setup?

I am trying to create a Linux OpenSwan VPN connection from Windows XP machine, using preshared key and the builtin Windows XP L2TP IPsec option.

I have followed the instructions in Linux Home networking Wiki for setting up OpenSwan and a guide to making it work with the Windows XP client, but am now stuck.

The net setup is as follows:

[my windows client, private IP A]<->[f/wall B]<-internet->[g/w X]<->[Linux OpenSwan server Y]
A - private subnet /24
B - internet address
X - internet address /24
Y - internet address on same subnet as X

What I essentially want is for computer with A address to feel and work, as if it was in X subnet for purposes of outgoing and incoming TCP and UDP connections.

My OpenSwan setup is as follows:

/etc/ipsec.conf (AAA and YYY indicates ip address parts of A and Y addresses):

conn net-to-net

the secret in /etc/ipsec.secrets is listed as:

B Y : PSK "0xMysecretkey"

where B & Y stand for respective IP adresses of gateway B and linux server Y

My L2TP WinXP setup is:

  • IP of destination: Y
  • don't prompt for username
  • security options: typical, require secured pass, don't require data encryption, IPSec PSK set to 0xMysecretkey
  • networking options: VPN Type: L2TP IPSec VPN; TCPIP protocol (with automatic IP address assignment) and QOS packet schedulers enabled

The error I get from Windows client is 789: "error during initial negotiation"


without (left,right)protoport=17/1701 you've configured the openswan side for tunnel mode ipsec, not transport mode to encrypt l2tp.

what does main mode debugging say on the linux end? i bet it's a protocol mismatch.

you can also turn on RAS debugging on the winXP side

  • thank you, i got a bit ill and haven't been able to pursue this further, but i'll get back to it, when i am on track. – Gnudiff Mar 17 '11 at 10:58

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